Orifice fitting

ABSTRACT

There is disclosed an orifice fitting having a flowway connectible in a pipeline and an orifice plate removably disposable across the flowway.

[45] June 18, 1974 8-/1936 Robinson et United States Patent [1.91 Aitkenl onirica FlrriNG Thisinvention relates generally to improvements inorifice fittings comprising a body having a flowway adapted to beconnected in a pipeline and an orifice plate adapted to be seated acrossthe flowway and thus in a position for measuring flow through thepipeline. In one of its aspects, this invention relates to improvementsin fittings wherein the orifice plate may be installed in and/or removedfrom operative position across the flowway under pressure and thuswithout shutting down the pipeline.

In this latter type of fitting, a housing is mounted on the body toprovide a chamber to one side of the flowway, and the chamber andflowway are connected through anopening in the housing to permit theorifice plate to be moved between its seated position across the flowwayand a position within the chamber. The orifice plate is so moved bysuitable means such as rthat shown in my prior U.S. Pat. No. 2,896,668,wherein the plate is carried by a nut non-rotatably mounted on athreaded shaft, whereby rotation of the shaft causes the nut to lmoveaxially along the shaft and thus the plate to move through theconnecting opening between its alternate positions; i

This connecting opening is adapted to be closed by a gate when the platehas moved out of the flowway into the chamber, whereby fluid within thechamber may be vented to the atmosphere without loss of pressure in thepipeline, and a door across an outlet from the chamber is adapted to beopened when the chamber has been so vented to permit removal of theplate. The plate is carried by an arm which is swingably mounted on thenut, so that upon opening of the door,

the plate may be swung with the arm to a position out-` side of thehousing to permit its replacement and/or repair. Upon return movement ofthe plate toward a position across the flowway, the door and chambervent are closed and fluid within the chamber is communicated with theflowway, so that the gate may be opened to permit the plate to movethrough the connecting opening. Y

ln one embodimentof the orifice fitting of my prior patent, all of thesesequential operations-are caused to occur automatically in response torotation of the threaded shaft. Thus, the gate is pivotally mounted onthe housing and normally urged to closed position, so as to isolate thechamber from the flowway, until it is engaged by the plate and swung toopen position as the plate moves from the chamber into the flowway.Also, a first normally closed check valve is mounted in the gate inposition to be engaged and opened by the plate, as it moves toward itsposition across the flowway, so as to equalize pressure in the chamberand flowway prior to opening the gate, and a second normally closedcheck valve is mountedin the housing in position to be engaged andopened by the nut, as the plate moves toward its position within thechamber, so as to vent the chamber subsequent to closing of the gateand-prior to opening the door for the outlet from the housing.

ln this same embodiment, a linkage is connected to the door and arrangedin a position within the chamber to be be engaged by the nut, so as tocause the door to open in response to further movement of the platetoward its position within the chamber. Finally, a pin is located withinthe chamber in position to engage the carrier arm and cause it to pivotabout the nut andV 2 thereby swing the plate through the open door inresponse to still further movement of the plate toward such position.

In this and other types of orifice fittings, the orifice plate is seatedwithin a recess across the flowway through the body connected in thepipeline, and rings of rubber or other resilient material about theperiphery of the plate are caused to seal against opposite sides of therecess, whereby fluid through the pipeline is confined to flow through.the orifice in the plate. The surfaces of the body against which theseal rings are engaged are eventually worn or defaced to such an extentthat they must be refinished, which normally requires lthat the body beremoved from the line, and it is an objectof this invention to provide afitting in which these sealing surfaces may be renewed without soremoving the body.`

Also, although the fitting disclosed in my prior patent represents aconsiderable advance in the art of fittings in which the plate may bereplaced and/or repaired under pressure, it would nevertheless bedesirable to simplify its construction, repair and operation, as well asthe manner in which the position of the plate at different sequentialoperations may be adjusted. lt is therefore an object of this inventionto provide fittings of this type which have-a minimum of separate parts.

Afurther object is to provide such a fitting in which the mechanismwithin the housing for moving the orifice plate is of more compactconstruction, so that the area of the housing over which fluid pressureis effective may be materially reduced.

Still another object of the invention is to provide such a fittinghaving a means for easily and quickly adjusting the position of theorifice plate at 'the time it is swung through the outlet from thehousing.

These and other objects are accomplished, in accordancewith theillustrated embodiment of the invention, by an orifice fitting having asaddle adapted to be seatedin the recess in a position for receiving theorifice plate in its seated position across the body flowway. The saddlehas side walls with. ports therethrough adapted to be aligned with theflowway and an opening adapted to be aligned with the recess opening topermit the orifice plate to be moved into and out of seated positionfAseal ring about the periphery of the plate is adapted to seal againstthe inner sides'of the saddle side walls, and seal rings on the outersides of such walls are adapted to seal against the opposite sides ofthe recess. More particularly, the saddle is removable from the recesswhen its seal rings or sealing surfaces require replacement and/orrepair.

ln accordance with a further novel aspect of the invention, the functionof the two check valves in the fitting of my prior patent is performedby a single valve which is mounted on the housing within the chamber formovement between a first position connecting the chamber with theflowway and a second position connecting the chamber with the exteriorof the housing. More particularly, the valve is caused to move from itsfirst to its second position in response to movement of the plate: intoa predetermined position within the chamber, during its movement awayfrom the flowway, whereby the gate may be closed before opening of theoutlet, and from its second to-its first position, in response tomovement of the plate from said predetermined position within thechamber during movement toward seated position across the flowway,whereby the gate may be opened after closing of the outlet. In theillustrated and preferred embodiment of the invention, the valve iscaused to rotatel between its position by a rod which .is mounted forrotation about its axis and parallel to a threaded shaft on which a'nutis nonrotatably mounted, and the rod is rotated to in turn causerotation of the valve by the engagement of a pin on the nut with acontoured groove on the rod.

In accordance withfurther novel aspects of the invention, a cam isfixedly mounted on the door, and a cam follower is fixedly mounted onthe nut for engaging the cam to cause the door to swing open, as theplate is moved into the chamber and upon venting of the chamber to theoutside of the housing. In this way,

the door is operated without a linkage or other moving parts susceptibleto breakage. Also, a pin extending into the chamber for engaging thecarrier arm for the plate to swing the plate through the outlet ismounted on the housing for adjustment from outside the housing, wherebythe timing of thes stage of the operation of the fitting may be adjustedwith ease after installation of the fitting. Still further` the housingis cylindrical and the shaft, rod, nut and carrier for the platearranged in a compact manner to reduce the crosssectional area of thehousing to a minimum, and thus lessen the loading on the connection ofthe housing to the body. For this purpose, the axes of the shaft, therod and the orifice plate, and the pivotal axis of the carrier arm aredisposed generally in a plane passing through the axis of the flowway,and the shaft and rod are spaced approximately equal distances onopposite sides of the axis of the housing.

In the drawings, wherein like reference characters are used throughoutto designate like parts:

FIG. I is a vertical sectional view of a fitting con structed inaccordance with the present invention, seen along aplane transverse tothe axis of the flowway therethrough, and with the orifice plate seatedacross the flowway;

FIG. 2 is another vertical sectional view of the fitting, as seen alonga plane passing through the axis of the flowway;

FIG. 3 is a cross-sectional view of the fitting, as seen along brokenline 3-3 of FIG. l;

FIG. 4 is av horizontal sectional view of the vent valve assembly` asseen along broken lines 4-4 of FIG. 5;

FIG. 5 isa vertical sectional view of the vent valve assembly, as seenalong broken line 5-5 of FIG. 4;

FIGS. 6 and 7 are vertical sectional views of the fitting similar toFIG. 2, but during successive stages of movement of the orifice plateinto the chamber;

FIGS. 8 and 9 are additional vertical sectional views of the fitting,similar to FIG. l, but during still further movement ofthe plate intoand then out of the chamber;

FIGS. l0 and ll are perspective views of the door and a cam carriedthereon as'a pin on the nut moves into engagement with the cam tocauseit to swing the door from closed to open position; and

FIG. 12 is a perspective view of the saddle removed from the recessacross the flowway through the body.

With reference now to the details of the .abovedescribed drawings, thefitting, which is indicated in its entirety by reference character l0,includes a body Il having a flowway l2 therethrough adapted to be connected in a pipeline (not shown), and Ia housing 13 mounted on the bodyto provide a chamber 14 on the upper side of the body. As shown, thehousing is cylindrical and includes an intermediate portion l5 having anopen upper end which is closed by cap 16 and an open lower end which isclosed by a wall 17. An opening I8 through the wall 17 connects thechamber 14 and flowway 12 to enable an orifice plate 30 to be movedtherethrough between positions within the chamber, as shown in FIGS. 6to 9, and across the flowway, as shown in FIGS. l and 2.

Holes 12a and 12b in the body connect the flowway with the exterior ofthe body on opposite sides of the orifice plate 30, when the latter isseated across the flowway. As well known in the art, the outer ends ofthese holes are connected to manometers such that the pressure dropacross the orifice plate may be measured for calculating the flowthrough the pipeline.

The body 11 has a flange 19 on its upper side which supports the wall 17on the lower end of the housing 13, and the wall 17 in turn supports aflange 20 on the lower end of the portion 15 of the housing. The housingportion 15 and the wall 17 are releasably connected together and to thebody Il by means of bolts 2l which extend through aligned holes in theflanges 19 and 20 and wall 17 and are secured at opposite ends by nuts22. A pair of pins 23 extend through additional aligned holes in theflanges and wall and are -disposed at less than to one another, wherebythey insure that the housing is properly located circumferentially withrespect to the body when connected thereto by the bolts 2l. Ring gaskets24 form fluid-tight seals between each of the flanges I9 and 20 and thewall I7.

The body 11 also has a recess 25 which extends across the flowway andopens to the upper end of the body centrally of the flange 19, so as toreceive a saddle 35 in which the plate 30 is to be seated. As shown, therecess 25 is enlarged at its upper end 25a so as to permit a check valve26 pivotally connected to the lower side of the wall 17 to swingdownwardly from the position of FIGS. 6 to 9, in which it closes opening18, to the position of FIGS. 1 and 2, in which it is removed from theopening to permit the plate 30 to extend therethrough. The pivot pin 27upon which the valve 26 is mounted is surrounded by a spring 28 whichbears between the back side of the valve 26 and the bottom side of thewall 17 to normally urge the valve to the closed position.

As best shown in FIG. 2, orifice plate 30 has a rubber ring 3l about itsperiphery which is carried within a ring 32 at the lower end of an arm33. More particularly, the upper end of the arm is mounted on a meanswithin the chamber 14 for moving the orifice plate through the opening18 between the seated position of FIGS. l and 2 and positions within thechamber 14, as shown in FIGS. 6 to 8. When the orificev plate is inseated position across the flowway, thearm 33 of the carrier bearsagainst the check valve 26 to hold it in open position.

As best lshown in FIG. 12, the saddle is substantially U-shaped forfitting closely within recess 25 and includes spaced-apart side walls 36which are joined by a spacer 37 which is open at its upper end toreceive the orifice plate therethrough as the plate moves into and outof seated position within the saddle. As best shown in FIGS. 1 and 2,the upper end of the saddle terminates substantially flush with shelvesor shoulders 38 on opposite sides of the recess opening atthe lower endof its enlarged portion a.

Ports 39 are formedl in the side walls 36 of the saddl substantiallyconcentrically of its arcuate lower end. More particularly, these portsare of substantially the same diameter as the flowway l2 so that, whenthe sad'- dle is seated within the recess 25, they provide a substantialcontinuation of the flowway. Asshown in FIG. l, a pair of screws 41extend through holes in the body 1l and into holes 41a in the spacer 37of the saddle 35. As willbe apparent from FIG. l, these screws may beadjusted from the exterior of the fitting to dispose their inner ends ata desired position for adjusting the seating position of the orificeplate. i i

When the orifice plate is seated within the saddle, the opposite sidesof the seal ring 3l about its periphery will seal with the inner sidesof the side walls 36 about the opening 39. In like fashion, seal ringsonthe outer sides'of the saddle side walls surround the holes 39 andsealagainst the oppositely facing sides of the recess 25, so that fluidwithin the flowway is confined to flow through the orifice 31 of the`plate 30.

Each of the side walls of the saddle 35 is provided with a flange 36a atits upper end which extends outwardly above a shelf 38 of the openingfrom the recess 25 when the saddle is seated in the recess. The vsaddleis held down in seated position by bolts 3.619 `which extend through theholes in the flanges and into the tapped holes in the shelves.

As previously described, the saddle 35 provides a simple and inexpensiveway of renewing the sealing surface against which the seal ring 3l ofthe orifice plate 30 is disposed. Replacement of the saddle when itsseal surfaces are worn is possible merely upon disconnection of thehousing and body to permit the wall I7 to be raised above the enlargedupper `portion ofthe recessed opening 25.

As best shown in FIGS. I and 2, the upper end of car rier arm 33 issuspended from a nut 43 which is non- 'rotatably mounted on a threadedshaft 42 which is mounted vertically within the housing for rotationabout its axis. Thus, upon rotation of the shaft, the nut is caused tomove vertically alongit and thus cause the arm and plate 30 carriedthereby to be moved between positions across the flowway and within thechamber. More particularly, a rod 44 is mounted vertically within thehousing parallel to the .shaft 42, and alateral extension 45 on the nutis guidably slidable along the rod so as to hold the nut againstlrotation with the shaft. As shown, the lower end of the shaft isjournaled in wall 17, and the upper end thereof extends through a sealedbearing 46 in the cap 16 atthe upper endfof the housing. A noncircularpart 47 on the upper end of the shaft enables it to be engaged by asuitable tool for imparting rotation to the shaft. The upper and lowerends of the rod 44 are mounted in a manner tolbe described to follow.

The upper end of the carrier arm 33 is pivoted about the. nut extension45 for swinging about an axis lying generally within a plane through thevertical axes of the shaft 42 and rod 44, and thus generally within aplane through the axis of flowway l2. As best shown in FIG. 2, the shaftand rod are mounted substantially equal distances on opposite sides ofthe centerline of the housing, and the carrier arm is intermediate theshaft 42 and rod 44, and thus in position to move vertically through theopening 18,'in response to vertical reciprocation of the nut 43.

As can be seen from FIG. l, the opening 1S is of a size substantiallythe sameas the opening through the upper end of the saddle 35. The armisurged in a counterclockwise direction, as seen in FIG. 1, by means of atorsion spring 48 surrounding the nut extension 45 and engaging betweenthe extension and the arm. As a result, when the carrier arm movesupwardly through the opening 18, its righthand side will be urgedoutwardly` into a recessed portion or groove 49 in the side y of thehousing opposite an outlet 50 therefrom and a door 51 adapted to closethe outlet. As will be better understood from the description to follow,this permits the ring at the lower end of the carrier arm, and thus theorifice plate received in the ring, to be moved somewhat to the rightand out of the way of the door 51 as it swings open during a subsequentsequence 'of operation.

As previously described, upon movement of the orifice plate out of theopening 18 and into the chamber 14, the check valve 26 is automaticallymoved into closed position so as to isolate the chamber 14 from theflowway l2. At this time, the chamber 14 must be vented to the exteriorof the fitting so 'as to permit the `door 5l to swing inwardly to theopen position shown in FIGS. 8 and 9. Conversely, upon movement of theorifice plate to seated position across the flowway 12,

the .venting'of the chamber to the exterior of the fitting must bediscontinued Aand the chamber is instead vented to the flowway so thatpressureacross the check valve 26 may be equalized to permit it to beswung downwardly when engaged by the lower vend ofthe carrier.

This controlled venting is accomplished by means of a rotary valve 52which is removably mounted within a pocket 53 inthe top side of the wall17 of housing 14.

Thus, upon removal ofthe bolts 21, the wall I7 may be removed from theintermediate portion of the housing to permit access to the valveforreplacement or repair. As best shown in FIG. 2, a passageway 54 inthe wall 17 connects one side of the pocket with a vent pipe 55 leadingto the outer side of the wall 17, and a port 56 in the wall connects thebottom of the pocket 53 with the bottom side of the wallll7 withingasket 24, and thus with `the recess opening of the body 11. The valveincludes manifolding fixed tothe wall 17 and a disc 57 adapted toiberotated between positions to connect the chamber 14 with the `port54 tovent the chamber to atmosphere and to connect the chamber 14 with theport 56 to vent the chamber to the flowway l2.

Asbest shown in FIG. 5, the rotary disc 57 is received within an opening58 in aplate 59 held down on the top side of the manifold-and wall 17 bymeans of a retainer plate 60. The retainer plate is releasably connectedto the wall 17 by means of bolts 61 which extend through the plate 59and manifold, and the retainer plate, intermediate plate 59 and manifoldare releasably held together by means of bolts 62. Thus, upon release ofthe bolts 6l, the entire valve including the manifold and valve disc maybe removed as a unit for replacement or repair. Then, upon removal ofthe valve', it may be disassembled by removal of the bolts 62.

' Four equally spaced-apartholes 63 extend through the retainer plate inalignment with the upper ends of two pairs of holes 64a and 64b in themanifold. The holes 64a extend entirely through the manifold, while theholes 64b connect with a lateral passage 66 connecting at opposite endswith an annular recess 67 on the same level as hole 54. The valve disc57 is provided with a pair of diametrically opposed holes 65 which, inone alternate position of the valve disc (FIG. 2), are aligned with oneset of holes 63 and 64a so as to vent the chamber to the flowway. In theother alternate position of disc 57, the holes 64 are aligned with theother set of holes 63 and 64b, so as to vent the chamber to passageway54.

As previously mentioned, the valve 52 is caused to move between itsalternate positions automatically in response to movement of the nut43,and thus the orifice plate supported thereby. More particularly, theupper end of the rod 44 extends through a sealed bearing 44b in the cap16 and the lower end thereof has a boss 44a which is journaled axiallywithin valve retainer plate 60. An eccentric pin 70 on the boss extendsinto an eccentric hole in the valve disc 57, so that rotation of the rod44 about its axis will cause the valve disc to move between thealternate positions above described. The rod is caused to rotate bymeans of a pin 7l carried by the nut extension and received within agroove 72 formed in the side of the rod facing the shaft 42. Thus, asbest shown in FIG. 2, the lower end 'of the groove 72 is vertical, sothat during a substantial portion of the upward movement of the nut 43,the rod 44 is held against rotation, and thus the rotary valve is notmoved fromvthe position shown in FIG. 2, wherein it vents the chamber 14to the flowway I2. However, an intermediate portion of the groove 72bends at a small angle in a counterclockwise direction (looking down onthe rod) to cause the rod to rotate as the pin 7l moves through thebend. As illustrated in FIG. 6, the bend is so located along the lengthof the groove 72 that the carrier and orifice plate have first beenmoved upwardly into the chamber I4 and the valve 26 closed, so that thecheck valve 26 closes, the chamber is still being vented to the flowwayrather thanI to atmosphere.

' However, as the nut moves further upwardly, and the pin 7l on itsextensionmoves through the bent portion of the groove 72, the valve discis rotated to the position of FIGS. 4 and 5, whereby the chamber 14 isvented to the exterior of the fitting, as illustrated diagrammaticallyin FIG. 7. The upper end of groove 72 is also vertical so that therotary valve will be held in this position as the plate moves furtherupwardly into the chamber to open the door l and move the carrier ringand orifice plate outwardly through the outlet of the housing, asillustrated in FIGS. 8 and 9.

However, in order to return the plate to seated position across theflowway, the rotation of shaft 42 is reversed to cause the nut to movedownwardly along the shaft. As will be described to follow, this permitsthe carrier ring andplate to swing back into the housing and the door tobe returned to close position. Upon further downward movement of thecarrier and its plate to the position of FIG. 7, the pin 7l on the nutextension moves through the bent portion of the groove 72 of rod 44 soas to rotate the rod and thus the valve to the position illustrateddiagrammatically in FIG. 6 for venting the chamber 14 to the flowway l2.This of course prevents further. venting of the chamber to the exteriorof the fitting and equalizes pressure across the check valve 26, so asto permit the lower end of the carrier to move the gate Adownwardly toopen position upon still further lowering of the nut 43.

As best shown in FIGS. l and 2, the outlet 50 from the housing iselongated in a vertical direction to permit the carrier ring and orificeplate to be moved through it, as illustrated in FIG. 9. The inner sideof the cylindrical housing through which the outlet extends is flattenedto provide a flat surface about the periphery of the outlet againstwhich the flat periphery of the door 5l engages in its closed position.The door 5l is pivotally mounted on the housing within the chamber bymeans of pins which extend vertically from its upper and lower ends onone side thereof, and are received within bearing sleeves 82 mounted bybrackets 83 on the inner side ofthe housing above and below the door.

A cam 84 is connected directly tothe door at its upper end and along itsright side. As shown in FIGS. l0 and Il, the cam comprises a platehaving a lower portion 84A which extends generally perpendicularly tothe door 5I, an upper portion 84B which extends generally parallel tothe door, and an intermediate, reversely bent portion 84C. The camportion 84A is adapted to be engaged by a pin 85 mounted on ane'xtension 86 on the nut 43 as the nut moves upwardly within thehousing. More particularly, the extension 86 extends from a side of thenut adjacent the side from which the extension 45 extends, and thus in adirection perpendicularly to the axis of the flowway and toward theoutlet 5().

The door 51 is normally urged to closed position by means of a torsionspring 87 (FIG. 2) carried by a pin 88 held at its upper and lower endsby brackets 89 secured to the inner side of the housing and engaging atits opposite ends with the brackets and the inner side of the door. Thecam 84 and pin 85 are so located relatively to one another that the pin85 will move upwardly over the bent cam portion 84C only after the rod44 has been rotated to move the valve 57 to the venting position of FIG.7, at which stage the orifice plate is on a level generally opposite thelower end of the outlet 50. More particularly, and as previouslydescribed, at this stage of its upward movement the back side of thecarrier arm is urged into the recess 49 of the housing chamber so thatthe door 5I is free to swing open to the position of FIG. 8. Movement ofthe pin 85 over the cam portion 84B will cause the cam and thus the door5l to swing approximately 90 to the positions of FIGS. 8 and 11.

Upon continued upward movement of the nut, the pin 85 will move oververtical cam portion 84B to hold the door open, and a tapered surface 91at the upper end of the carrier will move into engagement with therighthand side of the lower conical end of a screw 92 mounted on the cap16 0f the housing. As will be understood from a comparison of FIGS. 8and 9, still further upward movement ot the nut will cause the carrierarm to swing in a clockwise direction, and thus move the arm and orificeplate through the outlet 50. During this continued upward movement ofthe nut, the pin 85 moves over the upper vertical portion 84B of the camso that it holds the door 51 in the open position.

Upon replacement of the orifice plate, shaft 42 is rotated in theopposite direction to cause the nut to again move downwardly and thecarrier arm to swing in a clockwise direction from the position of FIG.9 to the position of FIG. 8, therey moving the plate into the housingchamber. As the nut moves further downwardly, thepin 85 will movedownwardly over the bent portion 84C of the cam 84, thereby permittingthe spring 87 to urge the door 5I to closed position. Still furtherdownward movement of the nut causes the pin 71 to move through the bentportion of the groove 72 in rod 44 so as to rotate the rod and thus movethe rotary valve from the position indicated diagrammatically in FIG. 7to that indicated diagrammatically in FIG. 6. Asa result, the vent fromthe chamber is instead vented to the flowway. Continued downwardmovement of the nut moves the lower end of the carrier arm intoengagement with the top side of the check valve 26 to swing itdownwardly to the open position shown in FIGS. l and 2, and thus permitthe orifice plate to be lowered into seated position.

As best shown in FIG. 2, the top side of the check valve 26 is providedwith a cover 95 of rubber or other resilient material having a rib 96extending lengthwise of the check valve 26. This raised rib will beengaged by the lower end of the carrier arm for the orifice plate, andthus prevent rubbing of the lower edge of the carrier over the top sideof the check valve 26.

As best shown in FIG. l, the, screw 92 extends through a hole in the cap16 of the housing to permit it to be adjusted in a vertical directionfrom outside of the fitting. This is useful in regulating the positionat which the carrier is caused to begin its outward swinging motion,particularly after the fitting has been installed. The upper end of therod 44 above bearing 44h may be provided with any suitable marking forvisually indieating the position of the valve 52.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the apparatus.

It will be understood that certain features and subcombinations are ofutility and may be employed with out reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

As many possible embodimentsmay be madeof the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The inventionhaving been described, what is claimed.

l. An orifice fitting, comprising a body having a flowway therethroughand a recess extending across the flowway and opening to one side of thebody, a rigid, one-piece saddle having opposite side walls and portstherethrough, a spacer extending between the side walls to hold theirinner faces in fixed, spaced-apart, parallel relation, and an openingintermediate the side walls and spacer, said saddle being extendiblethrough the recess opening and into and out of a seated position withinsaid recess in which its ports are aligned with the flowway and itsopening is aligned with the recess opening, an orifice plate havingopposite sides which are parallel to one another, means mounting theplate on the body for movement in a fixed path transverse to the axis ofthe body flowway through the opening in the recess and saddle, when thesaddle is in seated position, into and out of a seated position betweenthe inner faces of the side walls of the saddle in which theorificetherein is aligned with the flowway and the ports in the saddle,resilient means on the outer faces of the side walls of said saddle andsurrounding the ports therethrough for sealing against the recess abouttheflow way, the opposite sides of the orifice plate fitting relativelyclosely between the inner faces of the saddle and having resilient meansthereon surrounding the orifice therein for sealing against the innerfaces of the side walls of the saddle about the ports therein, means forreleasably connecting said saddle to said body so as to hold the innerfaces of the side walls'of the saddle in fixed positions axially andtransversely `of the body -ably securing said flange to said shoulder.v

3. The orifice fitting of claim 1, wherein said spacer has holestherein, and said means for engaging the plate comprises screws carriedbythe body and extending through the holes at an acute angle withrespect to the transverse path of the plate so as to engage its endsurface.

4. An orifice fitting, comprising a body having a flowway therethrough,ahousing mounted on the bodyto` Y provide a chamber to one side oftheflowway;van d an opening in the housing connecting 'the flowway with thechamber, a threaded shaft mounted in the chamber for rotation about itsaxis, a rod mounted in the chamber for rotation about its axis andparallel to the shaft, a nut threaded on the shaft and held againstrotation therewith to cause the nut to move axially along the shaft inresponse to rotation of said shaft, an orifice plate carried by the nutfor movement through said opening between first and second positionswithin said chamber and across said flowway, respectively, a gateautomatically operable to close said opening, upon movement of saidplate therethrough and toward said first position, and to open saidopening, upon movement of the plate therethrough and toward said secondposition, means including a valve mounted on the housing for rotationbetween a first position connecting the chamber with the flowway and asecond position connecting the chamber with the exterior of the housing,means on the nut engageable with the rod for rotating the rod in onedirection, upon movement of the plate into a-predetermined positionwithin the chamber during movement toward its first position, and in theopposite direction,

upon movement of the plate beyond said predetermined position withinsaid chamber during movement toward its second position, and meansconnecting the rod to the valve for rotating said valve from its firstpo sition into its second position, in response to rotation of the rodin said one direction, and from said second position into its firstposition, upon rotation of said rod in said opposite direction.

5. The orifice fitting of claim 4, wherein the chamber has an open endover which'a wall is removably connected, the opening is formed in saidwall, and the valve is mounted on the wall for rotation about an axisparallel to the axes of the shaft and rod.

I way therethrough, a housing mounted on the body to provide a chamberto one side of the flowway, and an opening in the housing connecting theflowway with the chamber, a threaded rod mounted for rotation within thechamber, a nut threaded on the shaft and held against rotation therewithto cause it to move axially along the shaft in response to rotation ofthe shaft, an orifice plate carried by the nut for movement betweenpositions within the chamber and across the flowway, a gate for closingsaid opening as the plate moves into said chamber, said housing havingan outlet from the chamber through which the plate may be'passed, a doorpivotally mounted on the housing for swinging between positions openingand closing the outlet, means normally urging the door to closedposition, a cam fixedly mounted on the door, and a cam follower fixedlymounted on the nut and directly engageable with the cam, as said platemoves into said chamber and said gate is closed, to cause said door toswing from closed to open position.

8. An orifice fitting, comprising a body having a flowway therethrough,a generally cylindrical housing mounted on the body to provide a chamberto one side of the flowway, and an opening in the housing connecting theflowway with the chamber, a threaded shaft mounted for rotation aboutits axis generally within the chamber, a rod mounted in the chamberparallel to the shaft, a nut threaded on the shaft, an extension on thenut surrounding the rod to hold the nut against rotation and thus causethe nut to move axially along the shaft in response to rotation of theshaft, an arm mounted on the extension for pivoting about an axistransverse to the axis of the shaft intermediate the shaft and rod, anorifice plate carried by the arm for movement with the arm through saidopening between positions within the chamber and across the flowway, agate mounted on the housing for movement between positions opening andclosing said opening, said body having an outlet from the chamberthrough which the plate may be passed, and a door mounted on the housingwithin the chamber for movement between positions opening and closingthe outlet.

9. An orifice fitting of the character defined in claim 8, wherein theaxes of the shaft, the rod and the orifice in the plate, and the pivotalaxis of the arm are disposed generally in a plane passing through theaxis of the flowway` and the axes ofthe shaft and rod are spacedapproximately equal distances on opposite sides of the axis of thehousing. v

l0. An orifice fitting, comprising a body having a flowway therethrough,a housing mounted on the body and having a portion providing a chamberto one side of the flowway, said housing including a wall to separatethe chamber from said flowway and having an yopening therein connectingthe flowway with the chamfirst position, and to open said opening, uponmovement of the plate therethrough and toward said second position,means including a valve mounted in the wall for rotation between a firstposition Connecting the chamber with the flowway and a second positionconnecting the chamber with the exterior of the housing, and means forrotating said valve from its first position into its second position, inresponse to movement of said plate into a predetermined position withinthe chamber during vmovement toward its first position. and from saidsecond into said first position, in response to movement of said platebeyond said predetermined position within said chamber during movementtoward its second position.

ll. The orifice fitting of claim 1,0, wherein the wall is releasablyconnected to each of said housing portion and body, and, upon release ofits connection to said wall, said housing portion may be lifted from thewall without moving the valve from its second position.

12. An orifice fitting, comprising a body having a flowway therethrough,a housing mounted on the body and having a portion providing a chamberto one side of the flowway, said housing including a wall to separatesaid chamber from said flowway and having an opening therein connectingthe flowway with the charnber, an orifice plate, means within thehousing mounting the orifice plate for movement through said open ingbetween first and second positions within said chamber and across saidflowway, respectively, a gate automatically operable to close saidopening, upon movement of said plate therethrough and toward said firstposition, and to open said opening, upon movement of the platetherethrough and toward said second position, means forming a pocketwithin the wall and facing the chamber, a first means fluidly connectingthe pocket with the exterior of the housing, second means fluidlyconnecting the pocket with the flowway, a valve member removably mountedin the pocket for rotation between first and second positions and havingmeans therein for fluidly connecting the chamber with said firstconnecting means in its first rotative position and fluidly connectingthe chamber with the second con necting means in its second rotativeposition, and means for rotating said valve member from its first position into its second position, in response to movement of said plateinto a predetermined position within the chamber during movement towardits first position, and from said second into said first position, inresponse to movement of said plate beyond Said predetermined positionwithin said chamber during movement toward its second position.

13. An orifice fitting of the character defined in claim 12, whereinsaid first connecting means comprises a passageway extending throughsaid wall to connect the pocket with the outer periphery of the wall,and said second connecting means comprises a port extending through saidwall to connect the pocket with the flowl5. An orifice fitting,comprising a body having av flowway therethrough, a housing mounted onthe body to provide a chamber to one side of the flowway, and an openingin the housing connecting the flowway with the chamber, a threaded shaftmounted in the chamber for rotation about its axis, a rod mounted in thechamber for rotation about its axis and parallel to the shaft, a nutthreaded on the shaft, means on the nut surrounding the rod to hold thenut against rotation and cause the nut to move axially along the shaftin response to rotation of said shaft,an orifice plate carriedby the nutfor movement through said opening between first and second positionswithin said chamber and across said flowway, respectively, a gateautomatically operable to close said opening, upon movement ofsaid platetherethrough and toward said first position,fand to open said opening,upon movement of the plate therethrough and toward said second position,means including a valve mounted on the housing for movement between afirst position connecting the chamber with the flowway and a secondposition connecting the chamber with the exterior of the housing, meanson the nut engageable with therod for rotating the rod in one direction,upon movement of the plate into a predetermined position within thechamber during movement toward its first position` and in the oppositedirection, upon movement of the plate beyond said predetermined positionwithin said chamber during movement toward its second position, andmeans connecting the rod to the valve for moving said valve from itsfirst position into its second position, in response to rotation of therod in said one direction, and from said second position into its firstposition, upon rotation of said rod in said opposite direction.

1. An orifice fitting, comprising a body having a flowway therethroughand a recess extending across the flowway and opening to one side of thebody, a rigid, one-piece saddle having opposite side walls and portstherethrough, a spacer extending between the side walls to hold theirinner faces in fixed, spaced-apart, parallel relation, and an openingintermediate the side walls and spacer, said saddle being extendiblethrough the recess opening and into and out of a seated position withinsaid recess in which its ports are aligned with the flowway and itsopening is aligned with the recess opening, an orifice plate havingopposite sides which are parallel to one another, means mounting theplate on the body for movement in a fixed path transverse to the axis ofthe body flowway through the opening in the recess and saddle, when thesaddle is in seated position, into and out of a seated position betweenthe inner faces of the side walls of the saddle in which the orificetherein is aligned with the flowwAy and the ports in the saddle,resilient means on the outer faces of the side walls of said saddle andsurrounding the ports therethrough for sealing against the recess aboutthe flowway, the opposite sides of the orifice plate fitting relativelyclosely between the inner faces of the saddle and having resilient meansthereon surrounding the orifice therein for sealing against the innerfaces of the side walls of the saddle about the ports therein, means forreleasably connecting said saddle to said body so as to hold the innerfaces of the side walls of the saddle in fixed positions axially andtransversely of the body flowway, and means on the body for engaging theorifice plate to locate it in its seated position, upon movement in saidtransverse path.
 2. The orifice fitting of claim 1, wherein said bodyopening includes a laterally enlarged outer portion providing a shoulderon at least one side thereof, and said means for connecting the saddleto the body comprises a flange on the at least one side wall of thesaddle for extension over the shoulder, and fastener means releasablysecuring said flange to said shoulder.
 3. The orifice fitting of claim1, wherein said spacer has holes therein, and said means for engagingthe plate comprises screws carried by the body and extending through theholes at an acute angle with respect to the transverse path of the plateso as to engage its end surface.
 4. An orifice fitting, comprising abody having a flowway therethrough, a housing mounted on the body toprovide a chamber to one side of the flowway, and an opening in thehousing connecting the flowway with the chamber, a threaded shaftmounted in the chamber for rotation about its axis, a rod mounted in thechamber for rotation about its axis and parallel to the shaft, a nutthreaded on the shaft and held against rotation therewith to cause thenut to move axially along the shaft in response to rotation of saidshaft, an orifice plate carried by the nut for movement through saidopening between first and second positions within said chamber andacross said flowway, respectively, a gate automatically operable toclose said opening, upon movement of said plate therethrough and towardsaid first position, and to open said opening, upon movement of theplate therethrough and toward said second position, means including avalve mounted on the housing for rotation between a first positionconnecting the chamber with the flowway and a second position connectingthe chamber with the exterior of the housing, means on the nutengageable with the rod for rotating the rod in one direction, uponmovement of the plate into a predetermined position within the chamberduring movement toward its first position, and in the oppositedirection, upon movement of the plate beyond said predetermined positionwithin said chamber during movement toward its second position, andmeans connecting the rod to the valve for rotating said valve from itsfirst position into its second position, in response to rotation of therod in said one direction, and from said second position into its firstposition, upon rotation of said rod in said opposite direction.
 5. Theorifice fitting of claim 4, wherein the chamber has an open end overwhich a wall is removably connected, the opening is formed in said wall,and the valve is mounted on the wall for rotation about an axis parallelto the axes of the shaft and rod.
 6. The orifice fitting of claim 4,wherein the connecting means comprises a groove in the rod and a pin onthe nut slidable in the groove throughout the entire axial movement ofthe nut.
 7. An orifice fitting, comprising a body having a flowwaytherethrough, a housing mounted on the body to provide a chamber to oneside of the flowway, and an opening in the housing connecting theflowway with the chamber, a threaded rod mounted for rotation within thechamber, a nut threaded on the shaft and held against rotation therewithto cause it to move axially along the shaft in response to rotatiOn ofthe shaft, an orifice plate carried by the nut for movement betweenpositions within the chamber and across the flowway, a gate for closingsaid opening as the plate moves into said chamber, said housing havingan outlet from the chamber through which the plate may be passed, a doorpivotally mounted on the housing for swinging between positions openingand closing the outlet, means normally urging the door to closedposition, a cam fixedly mounted on the door, and a cam follower fixedlymounted on the nut and directly engageable with the cam, as said platemoves into said chamber and said gate is closed, to cause said door toswing from closed to open position.
 8. An orifice fitting, comprising abody having a flowway therethrough, a generally cylindrical housingmounted on the body to provide a chamber to one side of the flowway, andan opening in the housing connecting the flowway with the chamber, athreaded shaft mounted for rotation about its axis generally within thechamber, a rod mounted in the chamber parallel to the shaft, a nutthreaded on the shaft, an extension on the nut surrounding the rod tohold the nut against rotation and thus cause the nut to move axiallyalong the shaft in response to rotation of the shaft, an arm mounted onthe extension for pivoting about an axis transverse to the axis of theshaft intermediate the shaft and rod, an orifice plate carried by thearm for movement with the arm through said opening between positionswithin the chamber and across the flowway, a gate mounted on the housingfor movement between positions opening and closing said opening, saidbody having an outlet from the chamber through which the plate may bepassed, and a door mounted on the housing within the chamber formovement between positions opening and closing the outlet.
 9. An orificefitting of the character defined in claim 8, wherein the axes of theshaft, the rod and the orifice in the plate, and the pivotal axis of thearm are disposed generally in a plane passing through the axis of theflowway, and the axes of the shaft and rod are spaced approximatelyequal distances on opposite sides of the axis of the housing.
 10. Anorifice fitting, comprising a body having a flowway therethrough, ahousing mounted on the body and having a portion providing a chamber toone side of the flowway, said housing including a wall to separate thechamber from said flowway and having an opening therein connecting theflowway with the chamber, an orifice plate, means within the housingmounting the orifice plate for movement through said opening betweenfirst and second positions within said chamber and across said flowway,respectively, a gate automatically operable to close said opening, uponmovement of said plate therethrough and toward said first position, andto open said opening, upon movement of the plate therethrough and towardsaid second position, means including a valve mounted in the wall forrotation between a first position connecting the chamber with theflowway and a second position connecting the chamber with the exteriorof the housing, and means for rotating said valve from its firstposition into its second position, in response to movement of said plateinto a predetermined position within the chamber during movement towardits first position, and from said second into said first position, inresponse to movement of said plate beyond said predetermined positionwithin said chamber during movement toward its second position.
 11. Theorifice fitting of claim 10, wherein the wall is releasably connected toeach of said housing portion and body, and, upon release of itsconnection to said wall, said housing portion may be lifted from thewall without moving the valve from its second position.
 12. An orificefitting, comprising a body having a flowway therethrough, a housingmounted on the body and having a portion providing a chamber to one sideof the flowway, said housing including a wall to separate said chamberfrom said flowway and haVing an opening therein connecting the flowwaywith the chamber, an orifice plate, means within the housing mountingthe orifice plate for movement through said opening between first andsecond positions within said chamber and across said flowway,respectively, a gate automatically operable to close said opening, uponmovement of said plate therethrough and toward said first position, andto open said opening, upon movement of the plate therethrough and towardsaid second position, means forming a pocket within the wall and facingthe chamber, a first means fluidly connecting the pocket with theexterior of the housing, second means fluidly connecting the pocket withthe flowway, a valve member removably mounted in the pocket for rotationbetween first and second positions and having means therein for fluidlyconnecting the chamber with said first connecting means in its firstrotative position and fluidly connecting the chamber with the secondconnecting means in its second rotative position, and means for rotatingsaid valve member from its first position into its second position, inresponse to movement of said plate into a predetermined position withinthe chamber during movement toward its first position, and from saidsecond into said first position, in response to movement of said platebeyond said predetermined position within said chamber during movementtoward its second position.
 13. An orifice fitting of the characterdefined in claim 12, wherein said first connecting means comprises apassageway extending through said wall to connect the pocket with theouter periphery of the wall, and said second connecting means comprisesa port extending through said wall to connect the pocket with theflowway.
 14. An orifice fitting of the character defined in claim 12,wherein the wall is releasably connected to each of said housing portionand body, and, upon release of its connection to said wall, said housingportion may be lifted from the wall without moving the valve member fromits second position.
 15. An orifice fitting, comprising a body having aflowway therethrough, a housing mounted on the body to provide a chamberto one side of the flowway, and an opening in the housing connecting theflowway with the chamber, a threaded shaft mounted in the chamber forrotation about its axis, a rod mounted in the chamber for rotation aboutits axis and parallel to the shaft, a nut threaded on the shaft, meanson the nut surrounding the rod to hold the nut against rotation andcause the nut to move axially along the shaft in response to rotation ofsaid shaft, an orifice plate carried by the nut for movement throughsaid opening between first and second positions within said chamber andacross said flowway, respectively, a gate automatically operable toclose said opening, upon movement of said plate therethrough and towardsaid first position, and to open said opening, upon movement of theplate therethrough and toward said second position, means including avalve mounted on the housing for movement between a first positionconnecting the chamber with the flowway and a second position connectingthe chamber with the exterior of the housing, means on the nutengageable with the rod for rotating the rod in one direction, uponmovement of the plate into a predetermined position within the chamberduring movement toward its first position, and in the oppositedirection, upon movement of the plate beyond said predetermined positionwithin said chamber during movement toward its second position, andmeans connecting the rod to the valve for moving said valve from itsfirst position into its second position, in response to rotation of therod in said one direction, and from said second position into its firstposition, upon rotation of said rod in said opposite direction.